In 1983, I initiated a program of selection and improvement in the species Acer truncatum. I obtained seed and seedlings from several sources that were planted out for evaluation. As part of this program, in March of 1988, I selected four particularly nice seedlings which I planted into a trial block in a nursery in Boring, Oreg. After several years of evaluation, I determined that one of these trees, which I designated Acer truncatum ‘D’ (unpatented) was the best in terms of foliage quality, form, and fall color. I allowed ‘D’ to develop seed from open pollination in the block with many other selected seedlings of Acer truncatum. In October of 1992, I collected this seed from Acer truncatum ‘D’ and grew them in a seedbed in Boring, Oreg. From this seed, I obtained 58 seedlings which I planted out into a nursery row in Boring, Oreg. in April of 1994. From these 58 seedlings, I selected the best eight to be saved and transplanted in 1997 for further evaluation. The remaining seedlings of this group of 58 seedlings were destroyed. Several years after picking the seed, the parent tree Acer truncatum ‘D’ was destroyed when the block was cleared due to crowding and my evaluations had determined that the selected seedling trees were superior to the seed parent ‘D’.
Of the eight selected seedlings that were transplanted in 1997, I selected the best single tree in August of 1998 which I designated as Acer truncatum ‘JFS-KW187’. My attention was first drawn to ‘JFS-KW187’ because of its very dense, compact, form and its strongly upright growth habit. I later discovered that this ‘JFS-KW187’ tree had superior fall color. In August 1998, I began asexual propagation trials by budding from the original ‘JFS-KW187’ tree onto Acer platanoides rootstock. From this vegetative propagation, I obtained six trees which I compared to the original ‘JFS-KW187’ tree. Subsequently, I vegetatively propagated additional small trial plots of six to twelve ‘JFS-KW187’ trees in 2004, 2007, 2008, and 2009. All of these trial trees were destroyed after evaluation except for one ‘JFS-KW187’ tree that was planted into a long term trial block in 2011 in Boring, Oreg., and eight other ‘JFS-KW187’ trees that were saved to become a future propagation source in a stock block in a nursery in Canby, Oreg. in 2013. My original tree of ‘JFS-KW187’ was moved to a long term trial block in Boring, Oreg. in February, 2002.
This asexual propagation in Boring, Oreg. by budding on Acer platanoides rootstock has shown that the characteristics of my new tree are firmly fixed in successive generations. Testing, evaluation, and comparison of Acer truncatum ‘JFS-KW187’ trees has convinced me that my new tree has superior form and appearance for landscape use.